General fact: 5141 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Mathematical fact: 5141 is the only four digit number that is reversed in hexadecimal.
Trivia: 5141 is an uninteresting number.
Historical date: January 27th is the day in 447 that the Walls of Constantinople are severely damaged by an earthquake, destroying large parts of the wall, including 57 towers.